General purpose personal computers have certainly had a revolutionary effect on the modern world. Only a few short years ago, it was inconceivable that only a few thousand dollars could buy an incredibly powerful machine capable of performing almost any imaginable task performed in the workplace or home. In a single day, the same general purpose personal computer could be instructed to calculate a complex mathematical equation, compose a letter to a friend, do a regression cost analysis on a spreadsheet, send a electronic mail message to the President of the United States, and instruct your toaster to make you a piece of toast.
While the general purpose computer is capable of doing just about everything, it has often been criticized for not doing anything particularly well. Many people clearly do not want to pay substantial sums of their hard earned money for a general purpose computer that does thousands of things they don't want to do, but doesn't do a good job at what they do want to do. This is particularly true in the area of information retrieval, where many people would love to have a well designed, cost effective electronic alternative to hard copy media such as newspapers, but don't want to pay thousands of dollars for a general purpose computer that does, at best, a mediocre job of performing this task. In addition, many information suppliers would love to provide rapidly changing information to a select group of consumers as they need it, when they need it, without the cumbersome overhead of a general purpose computer.